Hole cutter



. "l'fbl 4, 1930. P. A. cARsoN ET A1. 1,745,779

HOLE CUTTER Filed June 22. 1928 INVENTQRs `1 Patented Feb.V 4, y193.)

f UNITED STATESL ,i ,PAUL A. oARSoN, on PITTSBURGH, AND WILLIAM BROAD,oF vBEAVER nALLS,

- PENNSYLVANIA PATENT ori-rca H'oLE CUTTER y Application led .Tune v22,

- provide a hole cutter of the character described, Awhich includes acutting member directly connected to the ymotor shaft to rotate with thelatter, which will facilitate and expedite hole cutting operations, andwhich embodies a novel supporting element permitting of the engagementkof the work by ythe f device to allow K A high speed cutting operationsat-any angle. f

' I Further objects of the invention are to p-rovide'al device oftheclassl stated which'is simple in its construction andarrangement,4

j strong, compact, Vlight in weight, durable and efficient in its use,positive in its action,y conveniently operable, and Vcomparativelyinexpensive to manufacture and operate. j

With vthe foregoing and other objects in fview`which will appear as thekdescription proceeds, the inventionfresides in the combiand claimed, itbeing understood that changes nation andarrangement of parts and in thedetalls of construction hereinafter descr1bed in the precise embodimentof the invention herein disclosed can be made within thescope Of theclaims hereunto appended ywithout departing from the Vs'pirityof theinvention.

Inthe drawing wherein like numeralsof referenceV designate correspondingparts throughout the several v1ews2- f Figure lis a top plan view,partly in sec- Y tion, of a hole cutter constructed in accord- Y bularcutting member; f Referring in detail a'nce'with the invention. y yFigures 2 and 3y are', respectively, Side elevationand front end viewsof the device.

.Figure l4 isan enlarged end View of the tuto the drawinglrepresentsanelectriciA motor including a motor y to the rear end of thelatter.

housing 2 ,and an end plate 3 which is 4secured A motor handle v 4-isfixed to anddepends from the lowerfside of the motor housing-2 andcarries the termi- *Inals of the electric current conductors 5.

The 'motor 1 is Slidably mounted on a sup-l "portingframe' 6. The lattercomprises three 192s. serial No. 287,434.

cated at 7, 8 and 9. Thefslide rods 7 ,y 8 and 9 are identical in lengthand-have pointed forward ends 10.

The slide rods 7 and 8 extend through the motor housing 2 adjacent tothe periphery of the latter, and are diametrically opposed atrespectivesides of the housing 2. Each of the slide rods 7 and 8 further extendsthrough a pair of guide bosses, indicated at 11 and 12. The bosses 11project forwardly from the front wall of the motor housing 2, and thebosses 12 project rearwardly from the rear end plate 3.

The slide rod 9 extends longitudinally through the tubular motor shaft13, and is disposed centrally intermediate of the associated slide rods7 and 8. The rear ends of the slide rods 7, 8 and 9 are ixedly securedin a handle bar 14. The forward end portions of the slide rods 7 and 8are fixedly joined together by a cross-bar 15. The forward end portionsof the slide` rods 7 and 8are threaded as at 16. The cross-bar 15 issecured in position by clamping each end thereof between a pair of nuts17, which engage each threaded end portion 16, of respective slide rods7 and 8. f j f The motor shaft 13V projects forwardly yfrom the forwardmotor bearing 18, and is rigidly connected to the tubular cutting member19, by a coupling'sleeve 20. The latter overlaps the adjoining ends ofthe projecting motor shaft 13 and the tubular cutting member 19, and ismaintained in the securing position by a pair of set screws,respectively indicated at 21 and 22.

The cutting member 19 is longitudinally aligned with the motor shaft 13and projects through a centrally disposed aperture 23 formed in thecross-bar 15.l

The forward end of the tubular cutting member 19 is formed with cuttingteeth, respectively indicated at 24, 25, 26, 27, 28, 29, 30 and 31. rEheteeth 24 and 28 are disposed on the mean circumference of the tubularcutting member 19 and are diametrically opposed with respect to eachother. The teeth 26 and 30 are disposed inwardly of the circumference ofthe inner periphery of the cutting member 19 and are diametricallyopposed relatively to each other. The teeth 25, 27, 29 and 31 aredisposed outwardly of the circumference of the outer periphery of thecutting member 19, and are positioned alternately between the otherteeth 24, 26, 28 and 30, respectively.

The relative positions of the teeth 24, 25, 26, 27, 28, 29, 30 andc31,as above described and as clearly illustrated in Figure 4, are providedfor the purposel of cutting a groove,

during the hole cutting operation, that will provide ample clearance forthe successful that thearrangement be suoli as to provide ampleclearance for the operation of the cutting member 19. The clearanceprovided by the latter entirely eliminates friction' against the outerand inner peripheries of the tubular cutting member 19, and consequentlypermits of the exceptionally high speed hole cutting operations effectedby the direct connection of kthe cutting member 19 with the motor shaft13.

The cutting :member 19 is formed with a plurality of apertures or slots32, which are disposed adjacent to the cutting end of the cutting member19, and provided for the escape or passage of cuttings concomitant withhole cutting operations.

A collar 33, secured by a set screwf34, is

f adjustably mounted on the cutting member 19 and is provided for thepurpose of regulating the depths of the holes being cut.

When the motor l is shifted to the rearward position Von the supportingframe 6, as

shown in Figure 2, the forward pointedk ends 10 of the slide 'rods 7, 8and 9 will project slightly beyond the forward or cutting end of thecutting member 19, the slide rod 9 eX- tending longitudinally throughthe latter.

In practice, the operation of our improved hole cutter is as follows"Ihe running motor 1'with the associated cutting member 19 is firstshifted to the eXtreme rearward position on the supporting frame 6. Theprojecting pointed endsklO of the slide rods 7 8 and 9 are then forcedinto the work into which the hole is to be cut.

The operator supports the cutter' by grasping the handle bar 14 with onehand, and shifts the motor 1 forwardly on the supporting frame 6 by hisgrasp on the motor handle 4 with the other hand, thereby feeding thecutter member 19 into the work and vreadily effecting the hole cuttingoperation.

In cutting a hole with the tubular cutting member 19, in the mannerstated, Vthe corev resulting from the hole-cut, will, of course, bepositioned within the cutting member 19. This core will, however, bepushed from the cutting member 19 by the slide rod 9, when the motor 1is again shifted `rearwardly on the supporting frame 6 'for theysubsequent holeV cutting operation. n

'Ihe slide rod 9 not only serves as a medium for dislodging the corefrom the cutting member 19, but further provides a centering agent forsteadying the cutting operation of the latter and generally increasingits eiiciency.

By the adjustment of the collar 33, Yon the cutting member 19, holes ofany predetermined depth may be cut. In the event that it is not desiredto cut a hole through the work,-` theresulting corewould, of course,`remain in the hole until the same is broken or cut i therefrom; Thislatter operation may be readily accomplished by any suitableimplen n cment. I c c It will here be noted that the present inv vention isparticularly adaptable for elecy tricians or for other tradesmen whoseart callsV l instead of the tubular cutting member 19, as

herein shown and described.y

From the foregoing description, takenin connection with the accompanyingdrawing, the advantages of the construction and the method of operationwill be readily apparent to those skilled in the art to which theinven-lk tion appertains, and while describing the principle ofoperation ofthe invention together with thedevice providing anembodiment thereof, it isto bey understood that the device shown ismerely illustrative, and that various changes in the form, proportions,and details of construction may be resorted to without departing fromthev principle or Y sacrificing any of the advantages of the inventionas defined in the appended claims.

What we claim is: 1. hole cutter of the character described comprising-a supporting frame, Van electric motor including a shaft shiftablymounted on said supporting frame, a tubular cutter member directlyconnected with the shaft of saidelectric motor, the forward end of saidsupporting framek ybeing provided with Vwork engaging elements, saidelectric motor retractable on said supporting frame to disposeV theforward cutting end of said tubular cutting member rearwardly of saidwork ent gaging elements, said ksupporting frame includingy a slide rodextending through the said motor shaft and through said tubular cuttingmember and providing a centering medium for the latter. f

j 2. A hole cutter of the character described comprising a supportinglframe, a driving element including a shaft shiftably mounted onsaidsupporting fframe, a tubular cutter member directly connected withsaid shaft, the forwardend of said supporting frame being provided withwork engaging elements,

said driving element being retractable on said supporting frame todispose the forward cutting end of said tubularV cutter member frearwardly of said work engaging'elements,

said supporting frame including a slide rod which extends through saidtubular cutter member and providing a centering medium u for the latter.

f tures.

In testimony whereof we afifix our signa- PAUL A. CARSON. v WILLIAMBROAD. f

